Air conditioning system



March 22, 1966 J. P. MURDOCH Re. 25,990

C 0011' t 10/; e r

' INVENTOHI BY JOHN P. MURDOCH Maia 5 United States Patent Oflice Re.25,990 Reissued Mar. 22, 1966 25,990 AIR CONDITIONING SYSTEM John P.Murdoch, 204 Gleen Road, Ardmore, Pa. Original No. 3,186,183, dated June1, 1965, Ser. No.

412,647, Nov. 20, 1964. Application for reissue Sept.

17, 1965, Ser. No. 500,460

6 Claims. (Cl. 62183) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

The present invention relates to an air conditioning system for use inbuildings having refrigerated compartments, equipment, and the like.More particularly, the present invention relates to a system forutilizing the heat developed from the operation of the refrigerationunits for the purpose of providing sensible heat to other areas of thebuilding.

The invention has particular application as a modification to anexisting installation using a liquid coolant such as water for reducingthe temperature of the heat exchange medium used in the refrigeratingunits of. the installation and which employ a hot air system for heatingthe surrounding area.

A primary object of the present invention is to provide an airconditioning system using the sensible heat from the refrigerating unitsto heat the surrounding area and having novel controls to operate in ahighly efiicient and effective manner, effecting a considerable savingin heating fuel.

A further object of the invention is to provide a novel system modifyingthe conventional equipment which involves minimum additional apparatusand investment in the installation.

A further object of the invention is to provide an improved system whichoperates elfectively under normal conditions and which is also effectiveto avoid damage to the equipment in the event of power failure ormalfunctions in the system.

All of the objects of the present invention are more fully set forthhereinafter with reference to the accompanying drawing, wherein:

FIGS. 1 and 2 are schematic illustrations of air conditioning systemsembodying the present invention.

Referring to the embodiment shown in FIG. 1, the system is illustratedtherein in connection with a market building 10 having at least oneconventional refrigeration unit 11 for the compartments and/or displaycases and a substantially conventional hot-cold air conditioning systemincluding a conditioner l2 and a blower 13 for conditioning the air inthe building 10. The refrigeration unit 11 includes the usualcompressors, coils, and condensers with expansion valves having a supplyline 21 and return line 22 for the liquid coolant, normally water.

The supply line 21 is supplied from the sump 23 of a conventionalcooling tower 24 by means of a pump 25. The return line 22 from the unit11 is connected to the cooling tower by a conduit 26. The controls forthe unit 11 are conventional and are not illustrated or describedherein.

In accordance with the invention, the heated coolant in the return line22 may be diverted from the cooling tower 24 and used to add sensibleheat to the air conditioning system. To this end, a reclaimed-heat coil31 is included in the conditioner 12, in the present instance in advanceof the blower 13. This coil is connected at one side to the return line22 through a first branch line 32 and is connected at its other side tothe cooling tower sump 23 through a second branch line 33. Thus, theheated coolant from the condenser of the unit 11 may condenser in therefrigerating unit 11.

pass through the reclaimed-heat coil 31 to the cooling tower sumpinstead of passing through the cooling tower 24. To this end, theconduit 26 and the branch line 32 are each provided with a solenoidvalve downstream of their mutual connection. In the cooling towerconduit 26, the valve 27 is a normally-open valve operable to be closedwhen energized. In the reclaimed-heat branch line 32, the valve 37 is anormally-closed valve operable to be opened when energized. Thus, whenthe valves 27 and 37 are de-energized, the flow of coolant is asindicated by the arrows S from the return line 22 to the tower 24through the conduit 26. On the other hand, when the valves 27 and 37 areenergized, the flow of coolant from the return line 22 to the sump 23,is through the coil 31 and line 33 as indicated by the arrows W.

The energization of the valves 27 and 37 may be controlled by acontroller 41. The controller 41 maintains the valves 27 and 37de-energized during the summer months when the conditioner 12 issupplying cool air to the blower 13. During the winter months, on theother hand, the valves 27 and 37 would normally be energized so that thecoolant from the return line 22 is directed through the coil 31 to thecooling tower sump 23. When operating in the latter manner, the heatfrom the heated coolant return line 22 is not lost to the outsideatmosphere, but is recovered and used to heat the surrounding air in thebuilding 10, thereby reducing the amount of heat which must be added tothe conditioner 12 to maintain the building temperature at the desiredlevel. This effects a considerable saving in fuel for operating theconditioning during the winter months.

In order to prevent burning-out of a condenser in the refrigerating unit11, the coolant supplied thereto must be maintained below a certain safetemperature. The present invention provides a safety device to insurethat the coolant in the supply line 21 is maintained below thattemperature. To this end, a thermostat 43 is mounted in the coolingtower sump 23 to sense the temperature of the coolant in the sump. Ifthe temperature in the sump exceeds the safe level, the thermostat 43through a connection to the controller 41, operates to deenergize thevalves 27 and 37 closing the branch line 32 and opening the conduit 26to direct the heat exchange medium through the cooling tower until suchtime as the temperature of the coolant in the sump 23 falls a set amountbelow the safe level. Thus, the system of the present invention insuresagainst burning out of the By the same token, in the event of a powerfailure in the control circuit for the valves 27 and 37, the valves aredeenergized to cause the return line 22 to be connected to the sump 23through the cooling tower 24, insuring that the coolant is maintainedbelow the safe temperature level in the supply line 21.

Thus, the conditioning system of the present invention provides a simplebut fully effective means for utilizing the heat from the condenserreturn line to heat the building area. The system is readily installedin existing installations by simply adding a reclaimed-heat coil 31 tothe store conditioning unit, a pair of standard solenoid valves, and theassociated piping and controls. In accordance with the invention, thesystem insures the proper operation of the condenser and insures againstdamage to the refrigerating unit by maintaining the temperature of thecoolant supplied thereto below the danger level.

In some instances, the existing refrigeration system does not embody acooling tower, but rather utilizes fresh water as a coolant whichnormally discharged into the sewer or other drain after passing throughthe condenser. Such a system uses a considerable amount of fresh waterand may be modified in accordance with the present invention, forexample as illustrated in FIG. 2, in order to substantially reduce theconsumption of fresh water as well as to effect a considerable saving infuel. In this embodiment of the invention, the equipment in the marketbuilding 110 is identical to the equipment in the building 10 of theprevious embodiment and corresponding reference numerals have beenapplied thereto. The supply line 121 for the condenser is connected to afresh water supply line 124 through a check valve 129. The return line122 is connected to a branch 132 leading to the reclaimed-heat coil 31and to a drain conduit 126 through a normally-open valve 127 operablewhen energized to shut off the flow through the conduit 126 and operablewhen de-energized to afford flow into the drain 128 through the conduit126. In normal operation, when the valve 127 is tie-energized, thepressure of the supply 124 is sufiicient to cause circulation of thewater through the condenser and to the drain 128, thereby eliminatingthe need for a pump in the fresh water system. When it is desired tohave the water flow through the reclaimed-heat coil 31, a pump must beused. To this end, a pump 123, for example driven by a motor 136, isconnected in the line 133 from the coil 31 and discharges into thesupply line 121 through a check valve 138. When the valve 127 isenergized, the motor 136 is also energized to initiate operation of thepump 123 and cause flow through the reclaimed-heat coil 31. Whenoperating with fresh water, the check valve 138 prevents back flow intothe pump 123, and when operating with recirculated water, the checkvalve 129 prevents back flow into the supply line 124.

In this embodiment of the invention, a thermostat 143 is mounted in theconnecting line 133 upstream of the pump 123 and downstream of the coil31 so that when the temperature of the recirculated water is elevatedabove the safe level, the thermostat 143, through the controller 141,interrupts encrgization of the valve 127 and the motor 136 to terminatethe recirculation and introduce fresh water into the system until thetemperature of the water in the line 133 falls a set amount below thesafe level.

To prevent the build-up of excess pressure in the reclrculatory portionof the system, when the valve 127 and motor 136 are energized, a safetybypass 145, controlled by a pressure-responsive relief valve 146, isconnected from the line 133 to the drain 128. Thus, when pressure buildsup, for example because of the heating of the water, it is relievedautomatically through operation of the valve 146. If pressure falls, onthe other hand, it is restored automatically by the operation of thecheck valve 129 in the fresh water supply line.

In the operation of the systems of the present invention, thecontrollers are normally operated in conjunction with the controls forthe conditioner 12 so that use of the reclaimed-heat coil 31 is madeonly when the conditioner controls call for the addition of sensibleheat to the area of the building.

While particular embodiments of the present invention have been hereinillustrated and described, it is not intended to limit the invention tosuch disclosure, but changes and modifications may be made therein andthereto within the scope of the following claims.

1 claim:

1. In an air conditioning system for use in buildings havingrefrigerated compartments, equipment, and the like therein, said airconditioning system comprising a conditioner for the air in saidbuilding and a blower for discharging the conditioned air into saidbuilding, sald refrigerated compartments, equipment, and the like havingat least one refrigerating unit embodying a condenser operable to becooled by a liquid coolant, a line to supply liquid coolant to saidunit, and a line to discharge the heated coolant from said unit, theimprovement comprising a normally-open energizable valve in saiddischarge line, a first branch line connected to said discharge lineintermediate said refrigeration unit and said valve, a second branchline connected to said supply line, a reclaimcdheat coil in said airconditioning system adjacent said blower in the path of the air beingdischarged into the building by said blower, said coil being connectedat one end to said first branch line and connected at the other end tosaid second branch line to form a loop including said supply line, saidrefrigeration unit, said discharge line, said first branch line, saidcoil, and said second branch line, energizable means in said loopoperable when energized to afford flow therethrough and operable whende-energized to prevent flow through said loop, a controller operable tosimultaneously energize and de-energize both said energizable valve andsaid energizable means, and a thermostat responsive to the temperatureof the coolant flowing through said loop [downstream of said coil andupstream of said refrigeration unit] and operatively connected to saidcontroller, said thermostat being operable when the coolant in said 100pdownstream of said coil and upstream of said refrigeration unit exceedsa predetermined safe temperature level to interrupt energization of bothsaid energizable valve and said energizable means to thereby interruptflow of coolant through said loop when the temperature of said coolantrises above [a predetermined] said safe level and to re-energize bothsaid energizable valve and said energizable means when the temperatureof said coolant falls a set amount below said safe level,

2. An air conditioning system according to claim 1 wherein saidenergizable means in said loop comprises an energizable, normally-closedvalve, and including a cooling tower for cooling said coolant, saiddischarge line being connected to the cooling tower downstream of saidfirst cnergizable valve, a sump for receiving the coolant from saidtower, and a pump connecting said sump to said supply line, said secondbranch line being connected directly to said sump, said thermostat beingresponsive to the temperature of the coolant in said sump to controlenergization of both said normally-open and said normally-closed valves.

3. An air conditioning system according to claim 2 wherein saidthermostat is mounted in said sump to respond directly to thetemperature of the coolant therein.

4. An air conditioning system according to claim I wherein saidthermostat is mounted in said loop downstream of said coil and upstreamof said refrigeration unit.

5 [3]. An air conditioning system according to claim 1 wherein saidreturn line is connected to a drain downstream of said energizablevalve, and wherein said energizable means comprises a pump in saidsecond branch line, and including a pressure relief valve connected atone side to said second branch line in advance of said pump andconnected at the other side to the drain, said thermostat being mountedin said second branch line in advance of said pump.

6 [4]. In an air conditioning system for use buildings havingrefrigerated compartments, equipment, and the like therein, said airconditioning system comprising a conditioner for the air in saidbuilding and a blower for discharging the conditioned air into saidbuilding, said refrigerated compartments, equipment, and the like havingat least one refrigerating unit embodying a condenser operable to becooled by a liquid coolant, a line to supply liquid coolant to saidunit, and a line to discharge the heated coolant from said unit, theimprovement comprising a valve in said discharge line, a first branchline connected to said discharge line intermediate said refrigerationunit and said valve, a second branch line connected to said supply line,a reclaimed-heat coil in said air conditioning system adjacent saidblower in the path of the air being discharged into the building by saidblower, said coil being connected at one end to said first branch lineand connected at the other end to said second branch line to form a loopincluding said supply line, said refrigeration unit, said dischargeline, said first branch line, said coil, and said second branch line;energizable means in said loop operable when energized to afford flowtherethrough and operable when de-energized to prevent flow through saidloop, a controller operable to energize and de-energize said energizablemeans, said valve being normally open when said energizable means isdeenergized and closed when said energizable means is energized; and athermostat responsive to the temperature of the coolant flowing throughsaid loop [downstream of said coil and upstream of said refrigerationunit] and operatively connected to said controller, said thermostatbeing operable when the coolant in said loop downstream of said coil andupstream of said refrigeration unit exceeds a predetermined safetemperature level to interrupt energization of said energizable means tothereby interrupt How of coolant through said loop when the temperatureof said coolant rises above [a predetermined] said safe level and tore-energize said energizable means when the temperature of said coolantfalls a set amount below said safe level.

References Cited by the Examiner The following references, cited by theExaminer, are of record in the patented file of this patent or theoriginal 10 patent.

UNITED STATES PATENTS 2,797,068 6/1957 McFarlan 62159 2,883,836 4/1959Sacks 62267 WILLIAM J. WYE, Primary Examiner.

